The present invention relates to a method for delivering a pressurized fluid, such as hydrogen or another compressed gas, to a receiving tank, such as a vehicle fuel tank. Although the invention is discussed herein with regard to delivery of pressurized hydrogen gas to fuel tanks of hydrogen-powered vehicles, persons skilled in the art will recognize that the invention has other applications. For example, it may be used to deliver other pressurized fluids which may or may not be used as fuels, and the pressurized fluids may be delivered to various types of receiving tanks other than vehicle fuel tanks.
With the increasing interest in clean and efficient fuels, automobile manufacturers are designing and manufacturing hydrogen-powered vehicles that are powered by fuel cells or hydrogen internal combustion engines. Hydrogen is being tested in these vehicles and has the potential to be the fuel of choice in the future. These hydrogen-powered vehicles are in the development stage and manufacturers are performing extensive tests to improve the vehicles and related technologies. Since there is not an established hydrogen fueling infrastructure in place, some manufacturers are installing fixed hydrogen fueling stations at test sites and elsewhere. Testing is taking place throughout North America without sufficient capability to fuel the test vehicles away from the fixed hydrogen fueling stations.
Hydrogen-powered vehicles are also being demonstrated and promoted at public events to increase consumer awareness and interest. These events are taking place at many locations where hydrogen fueling is needed but is not available. Currently, hydrogen is delivered to these events in the form of liquid or as a cylinder product. BX cylinders, individually or in packs, may be used to provide hydrogen to customers. However, these cylinders are very heavy and difficult (expensive) to transport.
In view of the above, there is a need to refill fixed hydrogen fueling stations and mobile hydrogen fueling stations to fuel test vehicles and demonstration vehicles at public events.
Industry desires to deliver compressed gas to hydrogen-fueled vehicles at high pressures (e.g. at pressures of 5,000 psig or more). As the delivery pressure requirements are increased, the amount of residual gas remaining in the hydrogen storage vessels at a conventional dispensing station is increased. One or more storage vessels at the dispensing station must have a pressure greater than the delivery pressure requirement. When none of the storage vessels can provide compressed gas at the delivery pressure requirement, the vessels must be refilled.
Industry desires to reduce the amount of residual gas in the storage vessels prior to refilling the storage vessels. This will reduce the frequency of refilling the storage vessels.